The Wii (like the GameCube) was weird. It was more than fixed-function, but less than fully-programmable; you'd basically assemble a simple "pixel shader" by clicking together up to 16 operations from a hardcoded list, using up to 8 textures. ('TEV Stages' is the term to Google if you want the gory technical details)

If you were coming to it from the PS2 (like I was), it was super-freeing and amazing and so much more flexible and powerful than anything you were used to. But if you were coming to it from the Xbox (like many of my co-workers were) it was more like suddenly being handcuffed.